Various aspects of the present invention relate generally to exhaust systems and specifically to reducing toxic gas emissions from an exhaust flow.
Emissions of typical consumer gasoline (or diesel) powered vehicles include nitrogen, carbon dioxide, water vapor, and oxygen (in some cases), along with traces of nitrogen oxides, carbon monoxide, sulfur dioxide, and hydrocarbons. Some of those emissions (e.g., nitrogen oxides, carbon monoxide, sulfur dioxide, and hydrocarbons) are toxic. To reduce the toxic gases, catalytic converters are added to an exhaust path of automobiles. Typical catalytic converters combine oxygen with carbon monoxide and unburned hydrocarbons to create carbon dioxide and water. Other catalytic converters further reduce nitrogen oxides as well as reducing unburned hydrocarbons and carbon monoxide.
These catalytic converters require a warm up period to function properly. As such, during the first few minutes after activation, the most toxic gases are expelled. Therefore, some vehicles include a smaller pre-catalytic converter that heats up much quicker to reduce toxins during the startup phase of the regular catalytic converter.